Polly, have you ever read the Bible? I would suggest reading it, even if you already have (I am rereading it now). Ask God to guide you and show you the way. Read His Word. Follow it.
As far as the dress... I dress modestly. If men still lust, there is not much I can do (not saying they do). Regardless, I have to know that I am doing the right thing. I cannot purposely dress provocatively because I know it will cause men to lust. I do the right thing and if a man still does the wrong thing, well there isn't much I can do. Does that make sense?
Here are a few verses about modesty:
9 In like manner also, that women adorn themselves in modest apparel, with shamefacedness and sobriety; not with broided hair, or gold, or pearls, or costly array;
http://www.openbible.info/topics/modesty (several verses in this link).